1. Field of the Invention The present invention relates to a spindle bolt seal device for a gas turbine, which is constructed such that steam is used for cooling a gas turbine high temperature portions and is then recovered.
2. Description of the Prior Art A gas turbine, operating under high temperature conditions, is being developed with a recovery type steam cooled system in which steam is used for cooling of high temperature portions and, after used for the cooling, the steam is recovered.
In the recovery type steam cooled system, the steam that has been used for cooling and then recovered, is effectively used for performing another work, and thus preventing the steam from leaking uselessly before it is recovered leads to enhancement of the cycle efficiency. Moreover, if the steam for cooling mixes into a gas path of the gas turbine, there is a fear of lowering the performance of the gas turbine itself.
On the other hand, first to fourth stage discs and end rotors of the gas turbine are fastened so as to be connected to each other by a spindle bolt and an outlined structure thereof is shown in FIG. 7. In FIG. 7, numeral 01 designates a first stage disc, which carries a first stage moving blade 04, numeral 02 designates a second stage disc, which carries a second stage moving blade 05 and numeral 03 designates a third stage disc, which carries a third stage moving blade 06.
Numeral 1 designates a spindle bolt, which passes through the discs 01 to 03 to connect them. Cooling steam flows into the respective moving blades from each of the discs, as shown by arrows, and is collected so as to be recovered into cavities formed between the discs.
In the prior art gas turbine, as shown in FIG. 6, no seal is provided for the spindle bolt 1, but rather there is a clearance 9 between a disc 8 and the spindle bolt 1 in a bolthole 2 so as to be appropriate for cooling of the spindle bolt 1. However, in the gas turbine which employs the recovery type steam cooled system, spaces between each of the discs 8 are filled with steam, hence there is a problem in that the steam leaks toward the upstream side through the clearance 9 between the disc 8 and the spindle bolt I to mix into the gas path.